Nutrients

Question 1

Food and Nutrients

Answer 1

• food can be derived from plant or animal sources

- provide energy and nutrients used by the body for maintenance, growth and repair

Question 2

Carbohydrates

Answer 2

• carbohydrates can be divided into 2 categories

1. Simple
2. Complex

• carbohydrate = 4 kcal/gram
• kilocalorie: amount of heat required to raise the temperatures of 1 kg of water 1 degree Celsius

Question 3

Complex Carbs

Answer 3

• higher in nutritional value compared to simple carbs
- eg. whole grains, leguminous plants and vegetables

• due to complexity, they take longer to digest and don’t raise blood sugar levels as rapidly
• act a body’s fuel and contribute significantly to energy production

• polysaccharides (starches, fibers)
- 3 or more CH2O units

Question 4

Lipids

Answer 4

• organic substance that are insoluble in water

Fats: solid at room temperature

Oils: liquid at room temperature

• fats and oils are both made of molecules called triglycerides

Question 5

Lipids: Saturated Fats

Answer 5

• single carbon-carbon bonds

* solid at room temperature

Question 6

Trans Fatty Acids

Answer 6

• occurs naturally in milk and some meats (these are beneficial)
• most trans fatty acids consumed is processed and manufactured (fast food, junk food)
• TERRIBLE
- raises level of ‘bad’ cholesterol
- leads to cardiovascular diseases

Question 7

Lipids: Sterols

Answer 7

• lipids with a distinctive multiple ring structure

* found out in most animals (insignificant amounts in plants)

Question 8

Lipids: Cholesterol

Answer 8

• key component of hormones (eg. Estrogen, Testosterone)

* integral part of the cell membrane (serves as the starting material for many compounds)

Question 9

Proteins

Answer 9

• proteins are chains of numerous amino acids put together
• each amino acid (unit) is linked together by a peptide bond

Amino acid 1 + Amino acid 2 -> Peptide

• sequence and number of amino acids in the protein is determined by the DNA in the nucleus of the cell

Question 10

Tertiary Protein Structure

Answer 10

• occurs when certain attractions are present between alpha helices and pleated sheets

Question 11

Quaternary Protein Structure

Answer 11

• is a protein consisting of more than one amino acid chain

Question 12

Essential Nutrients

Answer 12

• are materials needed for cell metabolism that cannot be synthesized
• vitamins are organic molecules needed in trace amounts for normal growth and metabolic processes

Question 13

Minerals

Answer 13

• inorganic molecules that are required for cell functions
- eg. Fe carries oxygen, Na: maintains fluid and electrolyte balance, assists in nerve impulse transmission and muscle contraction, P important to liberalization of bones and found in genetic materials

Question 14

Composition of Foods

Answer 14

• 6 classes of nutrients
- Inorganic:
> minerals, water
- Organic:
> carbohydrates, lipids, proteins, vitamins
• Non-nutrients:
- fiber, alchohol

Question 15

Simple Carbs

Answer 15

• very little nutritional value to the body
- ie. White flour, candy, chocolate, fruit juice, soda
- digested by the body very easily
• Monosaccharide (glucose, fructose)
- 1 CH2O unit
• Disaccharides (sucrose, lactose)
- 2 CH2O unit

Question 16

Lipids: Unsaturated Fats

Answer 16

• double bonds are present

* liquid at room temperature

Question 17

Lipids: Omega Fatty Acids

Answer 17

• commonly found in marine and plant oils
• Omega number is dependant on the location of the first double bond relative to the methyl end (CH3)
• benefits:
- reduces inflammation
- helps lower risk of heart disease, cancer, arthritis

Question 18

Phospholipids

Answer 18

• a glycerol with two fatty acids and one phosphate group
• the phosphate (PO4 -3) is negatively charged (polar and therefore is WATER SOLUBLE
• the fatty-acid chains are neutral (nonpolar and therefore WATER INSOLUBLE

Question 19

Lipids: Roles of Sterols

Answer 19

• bile acids
- emulsifiers of fat
• sex hormones 
- testosterone, estrogen
• adrenal hormones 
- cortisol
• vitamin D
* Note: Good/Bad cholesterol is not ingested. It is dependant on how the body processes/transports it

Question 20

Proteins: Amounts

Answer 20

• body uses 20 amino acids to make proteins
• 11 - non essential (body makes them)
• 9 - essential (obtained only through diet)
• protein ~ 4 kcal/g

Question 21

Proteins: Polypeptide

Answer 21

• when many peptides are linked together they form a polypeptide
• a polypeptide is NOT a protein until it has gone through a series of structural folds
- forms the protein’s final 3D structure
- the shape determines its properties and functions

Question 22

Primary Protein Structure

Answer 22

• a sequence of a chain of amino acids

Question 23

Secondary Protein Structure

Answer 23

• occurs when the sequence of amino acids are linked by hydrogen bonds

Question 24

Fat Soluble Vitamins

Answer 24

• can be stored in the body (fat tissue)
- ie. Vit. A, D, E, K
• absorbed first by lymph than blood
• can accumulate and become toxic 
• remains in fat stores 
• should be taken periodically

Question 25

Water Soluble Vitamins

Answer 25

• cannot be stored in the body
- ie. Vit. C, B
• absorbed directly into blood
• are secreted daily and must be consumed daily 
• stored in water filled compartments 
• should be taken frequently